Labour leader Isaac Herzog is losing control over his party as more Knesset members openly attack him and the party plummets in the polls.

Surveys conducted last week, a year after the previous election, showed Zionist Union (the joint list of Labour and Tzipi Livni's Ha'tnuah) receiving only 15 Knesset seats, down from the 24 it won in the election.

In a closed meeting of the party's parliamentary faction last week, Mr Herzog lost one of his key supporters, MK Erel Margalit, who demanded the party bring forward its leadership election and accused Mr Herzog of "putting the party in the freezer".

Mr Margalit, a high-tech entrepreneur, is expected to join a growing list of challengers including former leaders Shelly Yachimovich, Amir Peretz and MK Omer Bar Lev, a former colonel. Tel Aviv Mayor Ron Huldai is also considering a run.

On Monday, rumours began circulating that Mr Herzog was on the brink of reaching a coalition deal with the prime minister. It transpired that there was no deal in the offing, at least not yet. "Even if there was a deal," said one Zionist Union MK, "I doubt any of us would follow Bougie into a coalition."